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  5. Using Photocell times with Chip times or Summit data

Using Photocell times with Chip times or Summit data

This document assumes that you are using a photocell that can be plugged into a Summit Timer, and are already familiar with the operation of Summit Timers and your specific model of photocell.


FIS sanctioned races require that a photocell be used as the primary timing device. Photocells are accurate however they have many other limitations that need to be acknowledged and worked around if they are to be used. These are:

  • They provide a time but do not associate that time with racer numbers.
  • They have difficulty handling groups of racers that finish together. They can sometimes record one racer twice or if the delay threshold is too high they can miss racers entirely. 
  • They can be triggered accidentally by volunteers or by the weather if there are strong winds or loose snow.

To get around these limitations photocells should always be used with backup devices and a manual bib order in order to make sure nothing is missed. This is a guide on how to setup those backup devices and how to use Times Grid which will help you sort through the data from various devices and assign times to racers.

Adding Devices

In the Course Setup section of the timing software, click on Select a Timing Device on the Finish timing point (this is generally the only timing point where photocells are used)

Here, add the summit that will be connected to the Photocell as the primary timing device on this timing point.  Next, click the button at the right edge of the timing point to open the options menu, and select the Edit Backup/Precall Devices option as seen below:

This opens a window where you can add other devices to the timing point:

Beside the Summit Timer you just added, you’ll see a dropdown to choose which type of times or channel you want to use.

  • If you only have a photocell plugged in to your summit, you can leave this as “all times”.
  • If you have another input connected to the summit such as a plunger, you can change this to select the channel number that the photocell is plugged into. This will ensure that only times from the photocell will be accepted.

Using GoChips with a Photocell

FIS rules specify that photocell times must be used for finish time for all racers, so for FIS sanctioned ski races (NorAm, Supertour, Nationals) you will always add the GoChip activator as a Backup Device.  Times from a backup device will never be automatically used for a racer, they will only be displayed in the times grid as an extra data source for reference.

To get chip times in the timing grid alongside the photocell times, click the Add a Backup Device button and select the GoChip activator in use at your finish line.

For intermediate times at FIS Sanctioned races, for provincial-cup or lower level ski races, or for other sports that do not have to comply with FIS rules, you can use GoChip as the primary time source and automatically assign times to all racers. Your GoChip Activator only needs to be used as a backup device at the finish line in FIS races.

Using Post+Plunge data from a Summit

If you do not have GoChips at your race, or if you have enough volunteers and just want an extra data source, you can also record finish times using a plunger connected to the summit, or the impulse key on the summit keypad.  Posted bibs will always be associated with the times on channel 1 by default. The impulse key also creates records on channel 1, so your plunger should always be plugged into channel 1.

Posting bibs directly on the photocell is not recommended, because it is too likely that an incorrect time (either from a volunteer walking in front of a photocell or from bad weather) will be recorded on the photocell and assigned to a racer.

If you are plunging times on the same summit as the photocell is connected to, make sure both the devices are limited to only the channel that times are being recorded on – do not use the “All Times” option.

Assigning Photocell Times to Racers

Times Grid

The Times Grid is a tool that displays all the raw data from various sources for a timing point. This can be useful to:

  • Line up equivalent times from different timing devices at a point. These are used for backup or redundancy.
  • Assign times from a Photocell to racers.

Navigate to Times Grid by going to the Timing page. There you will find a list of timing points. Click the Times Grid button beside the finish timing point to open the times grid as is shown below.

In the Times Grid, times are counted as equal (displayed on the same row) when they are within the combined accuracy of the devices they were recorded on.  For example, a time recorded on a device with an accuracy of 0.2 seconds and a time recorded on a device with an accuracy of 0.01 seconds will be counted as equal if they are within 0.21 seconds of each other. 

However If two times are recorded within the set accuracy, but with different racer numbers attached to them they will never be considered equal.

Setting Device Accuracy when using a Photocell as the Primary Timing Device

When using a photocell, it is important to correctly set the device accuracy.  The devices in the times grid are ordered by accuracy, with the left-most column containing times from the most accurate device.  Because the software does not know which devices are plugged into a summit, we use a default accuracy of 0.2 seconds for any times recorded on a summit.

Setting the Accuracy of the Photocell

A photocell should be able to record times to a thousandth of a second, so click the Set Device Accuracy button and enter an accuracy of 0.001 for the photocell. 

Setting Accuracy for Backup Devices

What you set as the accuracy of the backup device will vary depending on the type of backup device being used and, in the case of plunger times, the skill of the operator. The goal is to have as many of the backup times appear on the same row as the primary time in times grid. This will make assigning times to racers easier. Remember, times will appear on the same row if they are within the combined accuracy of both devices.

GoChip Activator as a backup device: We recommend setting the accuracy of an activator to 0.5 of a second when it is being used as a backup device. Though GoChip times are significantly more accurate for this, you need to take into account that racers might not have the Timing Chip on their leading leg when they cross the line. This would create a larger discrepancy between their timing chip time and the Photocell time however we still want them to line up  in the Times Grid.

Summit Times as Backup: When the backup device is a summit being operated manually by a volunteer what you set as its accuracy will depend on the skill of the volunteer. We recommend starting with 0.6 of a second. If your volunteer is accurate you can increase the accuracy. If they are not accurate you can reduce it. Devices with the same accuracy will be displayed in the order they were added to the timing point.

Once your device accuracy has been set click the Save button.

Assigning Times to Racers

As times are recorded, you will see them added to the times grid.  If times are equal to within the accuracy of the devices they are recorded from, they will be aligned on the same row:

In this example, the three columns  on the right are each displaying a time from one of the devices on this timing point:

  • The first column is our most accurate device, the photocell on Summit #1 Channel 9.  Because a photocell does not record racer numbers, this column is only times and no numbers.
  • The second column is the GoChip Activator, and you can see the chip code, not the racer number, is displayed in this column because that is what the device has recorded.
  • The third column is our plunger times and posted bibs.  In this example, the finish volunteer has not posted a bib for racer #3, but we were able to look them up based on the chip code.

The leftmost column on the screen indicates which racer the most accurate time on this row was assigned to.

Grey racer numbers are a suggestion, indicating that the time has not been assigned yet but that this is likely the racer the time belongs to.  Ton assign times, click that column and type in the bib number you want to assign the time to. Then, the “split” and “assigned” column will populate to indicate that the time has been assigned to the racer (truncated to the set precision for the race if necessary). This is pictured below.

The “assigned” column can also be edited manually in case you need to quickly adjust a racer’s time for any reason.  If a racer’s time is edited enough that it is no longer equal to the recorded times on that row the grid will be shifted so the assigned time is displayed on a separate line as is shown below.

Using a Bib Order Device

A common source of backup data from the finish line is simply to write down the order of finish on a piece of paper.  Then, if there are any discrepancies in the timing data or computer problems you can always fall back to at least the order of finish.

This paper record is also a useful tool for troubleshooting confusing finishes though, so it can be nice to have it displayed in the timing interface.  If you can get a volunteer to enter the order of finish on a summit keypad, you can add that summit as a “bib order device” on the timing point:

When displaying records from a bib order device, the times associated with those records are ignored, and only the racer numbers are displayed along the bottom edge of the times grid.  Clicking on a row in the times grid will automatically bring the matching position in the bib sequence into focus at the bottom of the screen.

Updated on December 28, 2018

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